DEVELOPMENT OF CEREBRAL SPECIALIZATIONS

描述：（改编自研究者摘要）：广泛的目标 是为了描述人类发展过程中依赖经验的变化， 大脑和测试的假设，他们是由多个， 特定的关键时期。 研究人员将描述 听觉剥夺对视觉系统功能组织的影响， 以及视觉-手动语言（美国手语）习得的影响 语言，美国手语）和延迟暴露于语言对 大脑不同语言系统的功能组织。 的 调查人员将测试不同的身份概念， 正常人视觉和语言研究中的子系统组织 成年人听力 他们将决定影响的性质和时间 当改变的经验影响这些正常发展的时期， 系统的研究先天和后来被淘汰的个人，并在 美国手语和英语的母语和后期学习者。 调查人员将记录 事件相关脑电位（ERPS）和血氧变化 水平采用功能磁共振成像（FMRI）， 描述神经激活的时间和位置， 一组受试者执行旨在激活特定方面的任务， 感官和语言功能。 他们将评估假设，提出了 我们之前的行为、ERP和FMRI研究表明， 在视觉系统的变化和功能特异性 语言系统，可以发生以下听觉剥夺和：1。 先天性耳聋的受试者更准确，显示速度更快， 当检测时，比正常听力的Ss更广泛的神经激活， 定位和关注视觉事件的边缘 字段; 2. 调节这种处理的神经系统 广泛存在于聋哑学生中，包括处理听觉信息的区域， 听力正常; 3. 语言中有几个不同的子系统 而它们依赖和改变的程度不同 语言经验; 4。 大脑中的神经系统有重叠 处理美国手语和英语的左半球，但也有 右侧颞叶和顶叶区域的广泛激活 仅用于处理ASL的半球。 由于这些研究将决定 在人类发展的多个不同时期， 从环境有最大的影响，结果将进行 具体的教育计划将在什么时候实施， 优化听力和聋哑儿童的发展。

DESCRIPTION: (Adapted From The Investigator's Abstract): The broad goals are to characterize experience-dependent changes in the developing human brain and to test the hypothesis that they are determined by multiple, specific critical periods. The investigators will characterize the effects of auditory deprivation on the functional organization of the visual system, and the effects of acquisition of a visual-manual language (American Sign Language, ASL) and the effects of delayed exposure to language on the functional organization of different language systems of the brain. The investigators will test different conceptions of the identity and organization of subsystems within vision and language in studies of normal hearing adults. They will determine the nature of the effects and the time periods when altered experience affects the normal development of these systems in studies of congenitally and later deafened individuals, and in native and late leamers of ASL and English. The investigators will record event-related brain potentials (ERPS) and changes in blood oxygenation levels employing functional magnetic resonance imaging (FMRI) to characterize the timing and the location of neural activation as these groups of subjects perform tasks designed to activate specific aspects of sensory and language functions. They will assess the hypothesis, raised by our previous behavioral, ERP and FMRI studies, that there is considerable functional specificity in the alterations in the visual system and the language systems that can occur following auditory deprivation and that: 1. congenitally deaf subjects are more accurate and display faster and more extensive neural activation than normal hearing Ss when detecting, localizing and attending to visual events in the far periphery of the visual fields; 2. the neural systems that mediate this processing are more extensive in deaf Ss and include areas that process auditory information in normal hearing Ss; 3. there are several distinct subsystems within language and these differ in the degree to which they are dependent on and modified by language experience; 4. there is overlap in the neural systems within the left hemisphere that process ASL and English, but there is also extensive activation of the temporal and parietal regions of the right hemisphere for processing ASL only. Since these studies will determine the multiple, different time periods in human development when specific inputs from the environment have the greatest impact, the results will carry implications for the time periods when specific educational programs would optimize development in hearing and deaf children.